1. Field of the Invention
The present invention relates to a facsimile machine having a function of receiving image data in response to a request-to-send, specifically to a facsimile machine which transmits/receives image data by using a telephone line whose call fee is low and which has a plurality of telephone lines for transmitting/receiving data.
2. Description of the Related Art
A conventional facsimile machine transmits/receives image data through one telephone line. Such a facsimile machine often shares one telephone line with a telephone set, and as a prior art technology for such a machine, Japanese Unexamined Patent Publication JP-A 63-87068 (1988) discloses a control method of recognizing information of a calling end and switching one telephone line to the facsimile machine or to the telephone set.
According to the prior art technology, when a call signal enters the facsimile machine shown in FIG. 16 via a telephone line 101 from the calling end, a call signal detecting circuit 119 detects it and outputs a call receiving signal indicative of that to a CPU 127. Receiving this call receiving signal, the CPU 127 changes over a movable contact 111a of a switch 111 to a terminal 111b to which a voice information sending circuit 121 and a response signal detecting circuit 123 are connected, and then inquires through the voice information sending circuit 121 with which of a telephone set 103 and a facsimile machine 105 the calling end desires to communicate. Then, in response to the voice information, a voice response or a transmission signal of a facsimile machine is returned from the calling end, so that the CPU 127 discriminates it and connects the line 101 to the telephone set 103 or to the facsimile machine 105.
Thus, by inquiring of the calling end about the desired communication counterpart and then connecting a communication device such as a telephone set and a facsimile machine to the telephone line, desired one of the plurality of communication devices sharing one telephone line can be reliably connected to the line.
A facsimile machine which has a plurality of telephone line terminals and changes over telephone lines to be used in accordance with the rate of use of each telephone line is described in Japanese Unexamined Patent Publication JP-A 5-219275 (1993). FIG. 17 shows this prior art facsimile machine. This prior art facsimile machine reads an original document to be transmitted by reading means 131 and outputs a received original document by output means 132. When a call is made from the outside, first line communication control means 135, second line communication control means 136 or third line communication control means 137, which are currently idle, receives the call. Line selecting means 134 decides the number of telephone lines to be used based on the number of original documents to be received, the rate of use of the telephone lines and storage means 133, and so on, and gives an instruction of receiving the call to the first line communication control means 135, the second line communication control means 136 or the third line communication control means 137. Then, the line communication control means which has received the instruction receives the call.
Such a prior art facsimile machine is capable of improving the rate of use of a facsimile line, reducing a stand-by time for receiving data and decreasing the probability of call loss from the outside, by storing a plurality of lines in one facsimile machine and deciding a telephone line for receiving a call based on the rate of use of the storage means 133, the number of original documents to be received and the state of each telephone line. However, the prior art facsimile machine changes over the receiving line depending on the use frequency of the telephone line as described above, and furthermore, it requires the operator to change over the state of connection manually when transmitting/receiving image data by changing over from one telephone line to the other.
Japanese Unexamined Patent Publication JP-A 1-191552 (1989) discloses another prior art facsimile machine. This prior art facsimile machine has a plurality of transmitting/receiving telephone lines. In the facsimile machine shown in FIG. 18, discriminating means 151 discriminates whether there is a line error after a line connection or not, i.e., whether a communication with the counterpart has failed or not, and gives a result thereof to telephone number changing means 162. When it is determined that the communication with the counterpart has failed due to the line error, the telephone number changing means 162 gives another telephone number specifying the same counterpart with the previous one to an auto-dialing function 154. After a predetermined period of time, re-dialing control means 152 activates the auto-dialing function 154 to which the other telephone number has been given so as to perform a re-dialing operation. When the communication with the counterpart fails due to a line error again, another telephone number specifying the same counterpart with the previous one is given to the auto-dialing function 154 to activate and make it perform another re-dialing operation after a predetermined period of time. Thereby, the probability to communicate with the counterpart right away can be increased.
However, because the prior art facsimile machine shown in FIG. 18 re-dials by using another telephone line after the elapse of the predetermined period of time since when the line error after the line connection has occurred, it takes a predetermined period of time until the re-dialing operation is performed by using another telephone line, and the receiving end might receive data transmitted from another facsimile machine during the predetermined period of time.
Accordingly, it is an object of the present invention to provide a facsimile machine which is capable of automatically utilizing a telephone line whose call fee is low and of suppressing a total communication cost, by recognizing a telephone line used by a calling end from a telephone number registered by the calling end and by comparing the call fee of this telephone line with that of telephone lines available for the receiver.
It is another object of the invention to provide a facsimile machine in which a time until re-dialing is shortened to increase the probability of connection between the calling end and the receiving end by changing over a telephone line currently selected by line selecting means to another telephone line and by immediately making another call when the receiver is busy.
In order to achieve one of the above-mentioned objects, in a first aspect of the invention, there is provided a facsimile machine having a function of receiving image data in response to a request-to-send, comprising:
a plurality of line connecting means (22a, 22b), each of which has a telephone line (LA, LB) for transmitting/receiving data;
calling number recognition means (4a) for recognizing a calling number of a calling end;
registering means (4a) for registering the telephone number recognized by the calling number recognition means (4a);
sending means (4a) for sending the telephone number registered by the registering means by using the second telephone line (LB) among the plurality of telephone lines (LA, LB); and
request-to-send control means (4a) for ending a pre-communication process of the first telephone line (LA) to disconnect the first telephone line (LA) at the point of time when a pre-process of the second telephone line (LB) is completed by the sending means (4a) and making a request-to-send through the second telephone line (LB).
According to the first aspect of the invention, the facsimile machine can make a request to send image data by using the other telephone line (LB) on the way of the communication operation so as to receive the image data, so that it can receive the image data through a line whose call fee is lower by utilizing a difference of call fees of subscribing telephone lines. Therefore, it is possible to shorten call time as well as suppress the total communication cost.
In a second aspect of the invention, the facsimile machine comprises:
telephone line recognizing means (4a) for recognizing a telephone line to which the calling end subscribes, from the calling number recognized by the calling number recognizing means (4a);
call fee comparing means (4a) for comparing a call fee of the telephone line to which the calling end subscribes, with that of the telephone line to which the receiving end subscribes;
telephone line selecting means (4a) for selecting a telephone line whose call fee is lower based on a comparison result by the call fee comparing means (4a);
registering means (4a) for registering the telephone number recognized by the calling number recognizing means (4a);
sending means (4a) for sending the telephone number registered by the registering means (4a) by using the second telephone line (LB) among the plurality of telephone lines (LA and LB); and
request-to-send control means for ending a pre-communication process of the first telephone line to disconnect the first telephone line at the point of time when a pre-process of the second telephone line is completed and making a request-to-send through the second telephone line, in the case where the call fee of the second telephone line selected by the telephone line selecting means (4a) is lower than that of the first telephone line used by the calling end.
According to the second aspect of the invention, the telephone line to which the calling end subscribes is recognized from the telephone number registered by the calling end, and a request to send image data is made by utilizing the other telephone line of the receiving end on the way of the communication operation in the case where the call fee of the telephone line to which the receiving end subscribes is lower than that of the telephone line to which the calling end subscribes, whereby a difference of call fees of the subscribing lines is utilized to automatically select a telephone line whose call fee is lower and to receive the image data. Therefore, it is possible to shorten call time as well as automatically suppress the total communication cost.
In order to achieve the other object of the invention, in a third aspect of the invention there is provided a facsimile machine having a function of receiving image data in response to a request-to-send, comprising:
a plurality of line connecting means (122a, 122b), each of which has a telephone line for transmitting/receiving data;
line selecting means (122c) for selecting a telephone line to be used when a plurality of telephone lines are connected; and
re-dialing means (122j) for changing over the telephone line currently selected by the line selecting means (122c) to another telephone line so as to immediately make a call, when the receiving end is busy.
According to the third aspect of the invention, when the receiving end is busy, the telephone line currently selected from among 122a and 122b by the line selecting means can be changed over to the other line so as to immediately make a call, so that a stand-by time during which no call is made to the receiving end can be shortened and the probability of establishing a connection to the receiving end whose line use frequency is high can be increased.
In a fourth aspect of the invention, the re-dialing means (122j) re-dials through the same line when the receiving end is busy, and changes over the telephone line currently selected by the line selecting means (122c) to another telephone line so as to re-dial when a number of times of re-dialing exceeds a predetermined number of times.
According to the fourth aspect of the invention, the re-dialing means (122j) re-dials through the same line when the receiving end is busy, and changes over the telephone line currently selected by the line selecting means (122c) to the other telephone line so as to re-dial when the number of times of re-dialing exceeds the predetermined number of times, so that the number of times of re-dialing to the receiving end can be increased within the predetermined period of time. Still more, the stand-by time in one line can be prolonged continuously as a result and this stand-by time can be used for transmitting/receiving new data while the re-dialing state is maintained.
In a fifth aspect of the invention, the facsimile machine comprises:
communication error detecting means (122i) for detecting that a line is disconnected due to a communication error in course of communication; and
re-dialing means (122j) for changing over the telephone line selected by the line selecting means (122c) and immediately starting to make a call to the receiving end by using the other telephone line when the communication error detecting means (122j) detects the communication error.
According to the fifth aspect of the invention, when a communication error occurs, the telephone line currently selected by the line selecting means (122c) is changed over to the other telephone line, so that a call can be immediately made. Therefore, a stand-by time during which no call is made to the receiving end can be shortened and the probability of establishing a connection to the receiving end whose line use frequency is high can be increased.